update

public/courses/prog-intro/homeworks/sum/sumbigintegeroctal/SumBigIntegerOctal.java

@@ -0,0 +1,42 @@
+// SumBigIntegerOctal.java
+
+import java.math.BigInteger;
+
+public class SumBigIntegerOctal {
+
+    public static void main(String[] args) {
+        BigInteger sum = new BigInteger("0");
+        for (String argument : args) {
+            StringBuilder number = new StringBuilder();
+            for (char c : argument.toCharArray()) {
+                if (!Character.isWhitespace(c)) {
+                    number.append(c);
+                } else {
+                    sum = sum.add(parseNumber(number));
+                    number = new StringBuilder();
+                }
+            }
+
+            sum = sum.add(parseNumber(number));
+        }
+
+        System.out.println(sum);
+    }
+
+    static BigInteger parseNumber(StringBuilder number) {
+        if (!number.isEmpty()) {
+            String numberString = number.toString();
+            int numberStringLength = numberString.length();
+            if (numberString.endsWith("o") || numberString.endsWith("O")) {
+                return new BigInteger(
+                    number.substring(0, numberStringLength - 1),
+                    8
+                );
+            } else {
+                return new BigInteger(numberString);
+            }
+        } else {
+            return BigInteger.ZERO;
+        }
+    }
+}